Axial crushing of Nylon and Al/Nylon hybrid tubes by FDM 3D printing

Fused Deposition Modeling (FDM), as one of the most popular 3D printing methods, has shown great potential in manufacturing customized safety components. However, the materials made by 3D printing show different mechanical properties in different directions due to the inherent anisotropic features of the printing process. In this paper, the axial crushing behavior of Nylon and Al/Nylon hybrid tubes is investigated. Quasi-static axial crushing tests are performed for single-cell and quadruple-cell tubes and energy absorption characteristics of the tubes are investigated. The nonlinear finite element code LS-DYNA is employed to simulate the tests and to further investigate the energy absorption performance of hybrid tubes with various configurations. Results show that Nylon tubes alone are not suitable for energy absorption due to the interlayer fracture during the folding, while Al/Nylon hybrid tubes can avoid the adverse effects of this fracture. The quadruple-cell Al/ Nylon hybrid tubes show highly improved energy absorption efficiency. Finally, theoretical expressions are derived to predict the mean crushing forces of the Al/Nylon hybrid tubes, and the predictions compare well with experimental and numerical results.